Superheater



Oct. l0, 1933. H. PEPERKORN ETAL SUPERHE'ATER Filed Oct. 6, 1931 3 Sheets-Sheet l A TTORNEY Oct. l0, 1933.. H, PEPERKORN. Er AL I 1,929,514

SUPERHEATER Filed Oct. 6, 19.31 3 Sheets- Sheet 2 A TTORNEY 4 oct. 10, 1933.

H. PEPERKORN m' AL 1,929,514

SUPERHEATER Filled 0G11. 6, 193], n 3 Sheets-Sheet 3 BYf, 4. MW/-MM/ A/TTORNEY Patented Oct. 10, 1933 SUPERHEATER Heinrich Peperkorn, Friedrich Wernpe, and Otto E. Hartmann, Cassel-Wilhelmshche, Germany, assignors to The Superheater Company, New

York, N. Y.

Applicaticn October 6, 1931, Serial No. 567,202, and inV Germany October 28, 1930 5 claims. (o1. 12a-462) The invention relates to flue superheaters for marine boilers and particularly to such cases in` which the return ends of the superheater loops extend freely into the return or combustion chamber to obtain a higher degree of superheat. In superheaters of this class it was customary right from the outset not to extend into the combustion chamber the return portions of all of the superheater elements lying in the flues but only those lying in the two or three rows nearest to the walls. This was done in order to leave as unobstructed as possible the interior of the return chamber so that there would be a free space between the ends extending into the chamber at the sides and top where the flame could develop freely and from which the ends of the dues could be readily examined and repaired. Of course this advantage 'brought about a diminution of the amount of superheater surface. The present invention has for its object to retain the advantages of the old arrangements and not only to make up for the loss of superheating surface but to increase the superheat further. A superheater in accordance with the present invention has the ends of the superheater loops extending into the return chamber act as radiant superheater surface in such a manner kthat only one row of tubes along the top and sides are equipped with elongated superheater loops and that the superheating surface of these units is increased in the return chamber. This increase is advantageously brought about either by having the superheater loops extend as simple loops into thereturn chamber, but to have these portions within the return chamber provided with ribs welded to them in a known way in order toincrease the heat abscrbing surface or secondly, by giving the superheater loops in the flues along the walls the form within the return chamber ot'loops bent back on themselves. In both cases theconvection heated surface of all of the superheater elements in the nues is increased by an augmented radiant surface along the side and top of the return chamber, whereas on the other hand all of the remaining area of the iiue sheet is accessible from the return chamber. ln order to support the portions of the `loops extending into the return chamber, there are advantageousiy used angles secured to the Aroof and side walls and formed with properly shaped slots. The flow of the steam which is to be superheated may be such that it traverses successively those elements which end withinthe nues and then those arranged along the walls and roof and which extend into therreturn chamber. During ring up the cooling steam which is sent through the superheater for the purpose of protecting it ilows through all of the superheater elements although this is usually not required for those which end. within the nues.l However, to minimize the amountoi cooling steam required in this connection, the arrangement is' most advantageously such that the superheater loops which extend into the return chamber are connected as separate groups tothe inter'stage steam header so as to form a preliminary superheater or a secondary superheaterV during the y ring up of the boiler which can be cooled independently oi the restrof the superheater. With such an arrangement the cooling steam used during iiring up vperiods will be sent only through the superheater elementshaving a .radiant surface located in the lues along the roof and side walls.` I

The drawings show several forms of the Vinvention by wayoi illustration. Fig. l shows the return or'combustion chamber of a marine return tubular boilertogetherwi'i'h the flues opening into the end, with a superheater of the most advantageous forni of the invention, the increasedradiant surface being formed by means of ribs welded to the tubes. Fig. 2 is across section on line 2 2 of Fig. l.y 3 is across sectionKV on line 3 3 of Fig. 1. Fig. l shows a variation in' 85v which the increase in the radiant heating -surface is brought'about by bending the elements back on themselves. Fig. Y5 is a cross section on line 5-5 of Fig. Ll. Figs. 6, 'l and 8 show an advantageous sequence of steam iiow wherein the extended superheater units ci the wall and roof f lues are connected as separate groups to the` superheater headers to form a unitary superheater; Fig. V6 showing a fragmentary end elevation of the flue sheet, while Fig. '7 shows at the left a 95 section on the broken line 7.-7 and at the right a vsection on the broken line '7d-7a of Fig. 6; Fig. 8 showing a vertical section through the'boiler o n line 8-8 oi Fig.` 6. Fig. 9 shows a partial section through the combustion chamber with the provisions for supporting the extended return portion of the superheater elements. A

In the drawings, 2 are the return or combustion chambers of the return tubular boiler, into which open the nues 3 most of'which are occupied by 105 superheater units. In each chamber all of the vinner flues are equipped with superheater units 4 of the usual type ending within the ues. A similar row along each of the side walls and the ,roof oi each of the return chambers 2 is occu- 110 pied with superheater elements which are extended into the vicinity of the rear wall, this extension being, in accordance with the invention, shaped so that an increased radiant superheating surface is presented.

In Fig. 1 the extended superheater loops 5 are for this purpose provided with ribs 6 welded to them, these ribs extending from the ues through the return chamber. As will be seen from Fig. 1, the over-all width of each element is kept such that it is not greater than the diameter of the ilue 3. In the case of the superheater loops adjacent to the roof these elements extend through to the rear wall without any twist, whereas the superheater loops adjacent to the side walls and equipped with the ribs the loops are twisted through as is seen from Fig. 2. Both the loops along the roof and along the side therefore present their broad side to the name. In the form of Fig. 4, the return portions of the superheater elements 8 which occupy the top and side iiues are bent back on themselves within the return chamber so that each loop has three iistead of one return bend. At the same time, the portions of the superheater loops which are bent back are twisted through 45 in order to present the greatest possible surface to the name. Such an arrangement of the superheater results in considerably increased superheat on account AYof the radiant surface that has been added, while it yet retains the advantage that the largest possible portion of the flue sheet in the return chamber `remains accessible. If the desired superheat cannot be reached with this arrangement in any particular case, the superheater elements in the ilues adjacent to those next to the wall and roof and which normallyend within the lues, might be extended into the return or combustion chamber by greater or shorter distance as indicated in. dotted lines in Fig. 7. On the other hand, if thefiorm of the invention shown in Figs..1 and 4 results in too high a degree of superheat, this can bevlowered to the desired point either by letting all the end pieces of the superheater elements forming a radiant heating surface extend into the return chamber a shorter'distance, or by restricting the extension to only a part of the superheater elements occupying the nues adjacent to the roof and walls. Inorder to secure the extended superheater ends in their position, there are advantageously used supporting members made oi angle irons 10 which are fastened to the roof and side walls of the return chambers and provided with slots ll corresponding to the outline of the superheater elements.` An advantageous ow sequence of the steam to be superheated can be gathered fromFigs. 6 to 8.A The boiler in this example is a three-now boiler and as usual in such a case there are provided two groups of superheater headers placed in the vertical position in front of the front flue sheet. Each group consists in the form illustrated of three chambers, one long chamber 14 lying next lto the ilue sheet, an angular' chamber 15 and a short chamber 16. From the latter two extend the distribution headers 17 and 18 to which are attached the lateral superheater elements 5, and

, distributing chambers 19 and 20 to which are atchamber 15. From here the initially superheated steam flows for nal superheating through the elements which are extended into the combustion chamber and which are attached to the headers 17, 18, 19 and 20, to be finally delivered to the superheated steam chamber 16 from which the steam flows in a highly superheated condition tothe engine. Of course the group arrangement could also be reversed so that the lgroup forming the radiant superheater forms the ini- 85 tial superheater and the elements which are not extended into the combustion chamber form the iinal superheater` However, the former sequence is preferable. The intermediate chamber 15 and short chamber 16 have connections 21 and 22 through .vhichcooling steam is supplied during firing up, suitable valves being of course provided in the supply line and drain. In this manner during iiring up the cooling steam is sent through the intermediate chamber 15 and the extended elements of the radiant superheater intothe short chamber 16 from which it is allowed to escape. Cooling steam can also through the connections on the intermediate headers 15 reach the elements which are not extended, without, hoW- ever, flowing through them. In this manner cooling steam for cooling the superheater during nring up is saved. In ordinary cases the extended superheater portions of the radiant super-.- heater can be made of ordinary steel. If required, however, these portions can be made out of special heat resisting material such as molybdenum steel.

What I claimis: Z 1. In apparatus of the class described, the com- 310 bination of a combustion chamber, a group of vertically alined flues leading from the chamber,

tubular superheater elements arranged in the ues, each ue containing only one loop extend-, ing into the ue from the end remote from the combustion chamber and comprising two horizontally alined pipes, the loops terminating at a point short of the combustion chamber except those loops in the rows of flues immediately ad-,` jacent to the walls of the combustion chamber, the loops in said rows extending into the combustion chamber and the pipe lengths constituting them all .being in planes parallel respectively to v the corresponding combustion chamberwall. f A

2. In apparatus of the class described, the combination of a combustion chamber, a group of vertically alinedflues leading from the chamber,

Ytubular superheater elements arranged in the ilues, each nue containing only one loop extenczl-` ing into the flue from the end opposite the combustion chamber and comprising two horizontallyv alined pipes, the loops in the outside vertical row on each side being extended into the combustion chamber and there each having itsconstituent pipe lengths arranged to lie within the projected area of the respective flues and to extend vertically over a materially greater width than the diameter of a single pipe, thereby exposing a materially increased surface to radiation from the flame in the combustion chamber. i4() 3. Inv apparatus of the class described, the combination of a combustion chamber, a group of vertically alined flues leading from the chamber, tubular superheater elements arranged in the flues, each flue containing only one loop extend- .L25 ing into the flue from the end opposite the combustion chamber and comprising two horizontally alined pipes, the loops in the outside Vertical row on each side being extended intothe combustion chamber and there each having its two constituent pipe lengths arranged vertically one over the other thereby exposing an increased surface to radiation from the flame in the combustion chamber.

4. In apparatus of the class described, the combination of a combustion chamber, a group of ues leading from it, tubular superheater elements arranged in the flues, some of said elements terminating short of the combustion chamber and others extending into it, the latter being connected to form a separate group Which may be separately cooled during ring up of the boiler.

5. Flue tube superheater for return tube boilers having return portions which in part extend freely into the return or combustion chamber, characterized by the fact that in order to get HEINRICH PEPERKORN. FRIEDRICH WEMPE. OTTO H. HARTMANN.

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